Optical fiber is now used in a variety of telecommunication applications because of its small physical size and high bandwidth capacity. Typically, multiple fibers are contained in an optical fiber ribbon or loosely enclosed in a buffer tube, and an optical fiber cable is manufactured to include several buffer tubes or ribbons. A plastic encapsulant surrounds the fibers within a ribbon or tube to protect and insulate the fibers from stress and bending.
Optical fiber cables with enclosed ribbons or tubes are conventionally manufactured and marketed in the form of reels. Oftentimes, during or after initial installation of an optical fiber cable, access to the individual fibers along the length of the fiber cable, commonly referred to as midspan access or entry, is required.
Current midspan access techniques, however, do not provide a means for easy and quick access to fibers with low risk of damage to fibers or fiber coatings. For example, cutting of the encapsulant with a knife blade or pin does not provide for easy control of the depth and position of a cut and often results in undesired cutting of an optical fiber or damage to the coatings on the fibers, which degrades the longevity or reliability of the fibers. In addition, initiating a peel of the encapsulant in the middle of a ribbon is difficult because the encapsulant is often a thin covering over the fibers and has a surface which is smooth and flat and sometimes coated with a water blocking gel.
Other midspan access techniques such as immersing a ribbon or tube in chemicals or heating for reducing the strength of the bond between the fibers and the encapsulant are extremely time consuming and can harm coatings and partially or completely alter or remove ink coloring identification on the fibers. In particular, the use of chemicals often requires post-cleanup of the fibers after access is obtained.
Beasley, William E., "Meeting the Demands of the Local Loop with Improved Ribbon Fiber Midspan Access", 1994 NFOEC Conference, pp. 401-409, incorporated by reference herein, describes a midspan access technique which requires that, after the outer covering of a cable is removed, two friction pads are placed on either side of a ribbon and forcibly moved against each other to focus the force applied to the pads on a particular span of the ribbon and weaken the bond of the encapsulant to the ribbon in that area. The removal of encapsulant by use of friction pads, however, often results in contact between the friction pads and the fibers which become exposed, thereby risking damage to the fibers or coatings on the fibers.
Therefore, there exists a need for a method and apparatus for accessing encapsulated optical fibers in midspan of an optical fiber cable which overcomes the disadvantages of the prior art techniques described above.